The present invention relates to seals for a pulse detonation engine. It finds particular application in conjunction with seals to limit or retard leakage between detonation tubes of a pulse detonation engine and will be described with particular reference thereto. It will be appreciated, however, that the invention is also amenable to other applications.
Turbojet engines are typically directly attached to aircraft inlets without an interface being required. A pulse detonation engine (PDE), on the other hand, includes an interface between the engine and an aircraft inlet. Pulse detonation engines impose different airflow demands on a high-speed inlet than do conventional turbojet engines. Turbojet engine systems require a constant and near-uniform airflow supply. The airflow demand of a detonation tube for a PDE is in a cyclic “on/off” manner. A valve distributes airflow by opening chambers to prevent the “on/off” airflow demand of each individual tube from causing a transient into the approaching airflow.
A combustion chamber of a pulse detonation engine is similar to a piston of an automobile gasoline engine. Air and fuel are injected into a chamber to form a combustible mixture with a detonation initiated by a spark source. In the case of a pulse detonation engine, the explosion creates a high-pressure wave that moves down the combustion tube to the exit. The large increase in pressure in the chamber results in propulsive thrust.
The cycle for each combustion chamber of the pulse detonation engine is as follows: airflow (oxidizer) fill, fuel injection, entrance close, and ignition. At the beginning of the propulsive cycle, the combustion chamber is opened to the inlet airflow supply. The chamber is then closed to the incoming airflow, thus eliminating the demand of airflow from the inlet. Fuel is injected into the combustion chamber and the mixture is ignited. The chamber then is re-opened for additional airflow for the next combustion cycle. A high-speed valve, such as a high-speed rotary airflow control, typically provides this opening and closing of the airflow supply port. A high-speed valve is used because high engine efficiency typically requires high combustion frequencies. U.S. Pat. No. 6,637,187 discloses such a high-speed rotary airflow control.
A seal is needed between the high-speed valve and an associated engine frame.
The present invention provides a new and improved apparatus and method for creating a seal between the high-speed valve and the associated engine frame.